JPH10148317A - Furnace and method for gasification of wastes - Google Patents

Abstract

PROBLEM TO BE SOLVED: To recover a fuel gas, a molten slug, a molten metal and/or low boiling point heavy metals by gasifying and melting wastes. SOLUTION: This melting furnace has a waste charging port 11-1 from which wastes are charged on the top, and a gas discharging port 3-1 to discharge a generated gas, and has a discharging port 9 for a molten slug and molten metals on the bottom, and also is equipped with tuyeres 5-1 to 5-3 divided into several steps (normally into three steps) in the height direction, which can blow a combustion supporting gas and an auxiliary fuel respectively independently into a furnace wall part. In addition, the melting furnace is constituted in a manner to be equipped with a means 71 which measures the level of charged wastes, a gasification melting furnace having means 20, etc., to measure temperatures in the furnace, and/or an upward blowing lance 24-1 and a dust collecting means 25. In this case, the recovering efficiency of an energy gas can be increased by recycling the recovered gas into the furnace.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a gas (hereinafter referred to as energy) which can be used as a fuel by gasifying organic substances contained in general waste and industrial waste (hereinafter simply referred to as waste). Gas) or low-boiling heavy metals contained in these wastes as dust, and ash and valuable metals (hereinafter also simply referred to as metals) contained in these wastes, respectively. The present invention relates to a gasification and melting furnace and a gasification and melting method for waste collected as molten slag and molten metal.

[0002]

2. Description of the Related Art As a method of treating general waste mainly composed of municipal waste and industrial waste mainly composed of shredder dust of discarded automobiles and home electric appliances, a method of landfill disposal or landfill disposal after incineration is known. Has been adopted. However, given the recent tight situation that it is extremely difficult to secure landfill sites, the incineration method generally used so far has been reviewed.

Further, instead of directly discarding the waste or landfilling it after incineration, the waste once reduced in volume and solidified, that is, RDF (Refuse Derived) is generally used.
Fuel is a solid fuel called waste-derived fuel) and then incinerated, and some have been put to practical use. Examples of the waste treatment system using this method include a TC-system by Japan Recycling Management Co., Ltd., a J-Catrel system by Ebara Corporation, and a recycling energy center concept in Mie Prefecture (No. 6). Of the seminar “Seminar on Solid Waste Fuel Technology”, June 28, 1996 (Environmental Planning Center).

On the other hand, from the standpoint of protecting limited resources, these wastes or RDF are not simply incinerated,
It is desirable to recover recyclable materials as resources (useful substances) or energy (heat energy).
The following are examples that are currently in practical use.

[0005] 1. Material recovery Separation and recovery of metals (aluminum cans, steel cans, etc.) Separation and recovery of plastics (PET bottles, etc.) Separation and recovery of waste paper (newspaper, etc.) 2. Material conversion and recovery Recovery of plastics as fuel oil by pyrolysis oil recovery Recovery of plastics as fuel gas by pyrolysis gasification Thermal energy recovery Steam recovery at the time of waste incineration Since the above item 1 is a pre-treatment method before waste, the recovery of useful substances from waste after separation must rely on the above two or three means. I can't. In particular, recently, general waste and industrial waste contain various substances due to changes in lifestyle (diversification). Chemical systems are in the spotlight.

[0006] As the gasification system, the following one can be mentioned.

A. Nippon Steel's coke bed type direct melting system (“Steel Industry Bulletin” No. 1674, 1996.
3.21 (Japan Iron and Steel Federation), "Fuel and Combustion" Vol. 61,
No. 8 (1994), pp. 572-578, and Tokuhei 7
The melting furnace main body is a single-stage tuyere vertical shaft furnace, into which coke and limestone are charged together with waste from the center of the furnace.
Inside the furnace, from the top, a preheating / drying zone (about 300 ° C), a thermal decomposition zone (300 to 1000 ° C), and a combustion / melting zone (1700)
８００1800 ° C.). In the preheating / drying zone, waste is heated and moisture evaporates. The dried waste gradually descends and moves to the pyrolysis zone where the organic matter is gasified. The generated gas is exhausted from the upper part of the furnace, is completely burned in a combustion chamber at a later stage, and heat energy is recovered by a heat recovery system such as a waste heat boiler.

[0008] On the other hand, the remaining gasified ash and inorganic substances fall into the combustion / melting zone together with coke. The coke is burned by the air supplied from the tuyere, and the heat causes the ash and inorganic substances to completely melt. The melt is adjusted to an appropriate viscosity and basicity by the charged limestone, and discharged from the taphole to the outside of the furnace.

In order to save coke, a method is disclosed in which a separate charging system for coke and waste is used to utilize the sensible heat of exhaust gas for drying and preheating of waste to increase the thermal efficiency of the furnace. (Japanese Patent Publication No. 7-35889).

B. NKK high-temperature gasification direct melting system ("Steel Industry Bulletin" No. 1674, 1996.3.21
(The Japan Iron and Steel Federation)) The melting furnace body is a vertical furnace having tuyeres divided into three stages in the height direction, and the flow formed by the dry distillate of waste maintained at a high temperature of about 1000 ° C. Waste is directly injected into the formation along with auxiliary fuel such as coke. By blowing air from the middle tuyere (two-stage tuyere) into the fluidized bed, part of the generated gas is burned and the temperature is maintained.

[0011] The dry distillate containing incombustibles descends to the moving bed at the lower part of the furnace together with the auxiliary fuel, and is burned and gasified at a high temperature by oxygen-enriched air from the lower tuyere (main tuyere). It is melted, dropped and separated from metal by the difference in specific gravity. On the other hand, the free board temperature is always 1000 by the air from the tuyere (three-stage tuyere)
The temperature is maintained at not less than ° C., thereby preventing the generation of tar components and the production of dioxins and their precursors.

C. Thermoselect method (Th
thermoselect (1995.5.26), PAR
T1 "Foundation for the continuos conversions of
The furnace used in this method is a pressurized tube type pyrolyzer that evaporates water in waste and pyrolyzes organic matter, combustion of pyrolysis residue (char) by oxygen, and melting of ash. In this furnace, the decomposition gas of organic matter from the pyrolyzer is first introduced to the middle part of the furnace. ,on the other hand,
The char descends to the bottom of the furnace, and is burned at a high temperature by oxygen to melt the ash. At the same time, conversion of organic decomposition gas to CO and H ₂ (gas reforming) proceeds in a high-temperature atmosphere at the top of the furnace.

However, the above conventional method has the following problems.

That is, the vertical shaft furnace of the above system A requires expensive coke and completely burns the generated gas, so that only the sensible heat can be recovered. Further, in this method, since the temperature of the preheating / drying zone in the upper part of the furnace is about 300 ° C., a large amount of hydrocarbons such as tar and dioxins which cannot be sufficiently decomposed are discharged outside the furnace. further,
Since low-boiling heavy metals are not sufficiently gasified and remain in the molten slag, coke is essential to reduce the slag.

The vertical furnace of the system B also requires expensive coke as in the case of the system A. this is,
This is because heavy metals having a low boiling point are not sufficiently gasified and remain in the molten slag, so that the slag is reduced. Further, in order to keep the free board always at 1000 ° C. or higher, a large free board is required, and an increase in the size of the furnace is inevitable.

Although the furnace used in the method C is said to have two reactors (furnace) connected integrally, it is actually clearly separated into two furnaces, a pyrolysis furnace and a combustion melting furnace. . Therefore, it is structurally complicated and the equipment cost increases. Further, since the pyrolysis furnace is an indirect heating type furnace separated from the combustion melting furnace, the sensible heat of the exhaust gas of the combustion melting furnace is not sufficiently utilized.

[0017]

SUMMARY OF THE INVENTION In connection with the problem of landfill sites, the present invention is to effectively use combustibles, ash, iron, etc. in wastes, and to reduce the costs associated with landfills. It is intended to utilize the by-product gas generated as fuel for power generation and the like.

That is, an object of the present invention is not to simply incinerate general wastes and industrial wastes, but to gasify organic substances contained in the wastes and collect them as energy gas, and to include the wastes in the wastes. Ash and valuable metals such as iron (Fe) and copper (Cu) are recovered as molten slag and molten metal, respectively, or mercury (Hg), cadmium (Cd), and lead (Pb) contained in waste. )
It is an object of the present invention to provide a method of recovering harmful low-boiling heavy metals such as harmful dusts, and a furnace therefor. Specifically, a series of steps of gasification and melting of waste, dehydration / pyrolysis, and gas reforming were carried out in one furnace without using expensive coke to solve the above-mentioned problems in the prior art. It is another object of the present invention to provide a gasification melting furnace and a gasification melting method capable of producing clean exhaust gas free of tar, dioxin, and the like.

[0019]

The gist of the present invention is to provide a waste gasification and melting furnace described in (1) and (3) and a gasification and melting method described in (2) and (4) to (6). is there.

(1) Gasification of vertical waste in which the waste is burned, the organic matter in the waste is gasified and recovered as an energy gas, and the ash and metals in the waste are recovered as a melt. A melting furnace, having a waste inlet for charging the waste and a gas outlet for discharging generated gas at an upper portion, and a melt slag and a molten metal outlet at a lower portion; Between the charging port and the discharge port of the molten slag and the molten metal, each has a tuyere divided into a plurality of stages in the height direction that can independently blow the oxidizing gas and the auxiliary fuel, Waste gas characterized by having means for measuring the level of the charged waste, means for measuring the temperature near the tuyere in the middle stage, and means for measuring the temperature of the atmospheric gas in the upper part of the furnace Chemical melting furnace.

(2) A method for gasification and melting of waste, which is performed using the waste gasification and melting furnace according to (1),
The waste was charged from the waste MonoSo inlet into the furnace, the reaction in each zone below, and energy gas mainly composed of CO and H _2, and molten slag and the molten metal, provided the former furnace upper A method for gasification and melting of waste, comprising recovering from a discharged gas outlet, and recovering the latter from a discharge port for molten slag and molten metal provided in a lower part of the furnace.

[First Zone] Amount of flammable gas and auxiliary fuel determined by the level value of the charged waste are blown from the lower tuyere, and the char generated in the second zone is burned, gasified and reduced. The ash and the metals contained in the carbide are melted together with the generation of the reactive gas to form molten slag and molten metal.

[Second Zone] Amount of the supporting gas and auxiliary fuel determined from the temperature measurement value near the middle tuyere are blown from the middle tuyere, and the reducing gas generated in the first zone is secondarily discharged. It burns, dewaters and heats the waste charged from the waste loading inlet to thermally decompose it into carbide and hydrocarbon gas.

[Third Zone] Amount of flammable gas and auxiliary fuel determined from the measured temperature of the atmospheric gas in the upper part of the furnace are blown from the upper tuyere to remove the hydrocarbon gas generated in the second zone. It is thermally decomposed into an energy gas containing CO and H ₂ as main components.

(3) Burn the waste, gasify organic matter in the waste and recover it as energy gas, and gasify low-boiling heavy metals in the waste and recover it as dust accompanying the energy gas. A vertical waste gasification and melting furnace for recovering ash and metals in the waste as a melt, wherein a waste loading inlet for charging the waste at an upper portion, and gas and dust generated And a dust recovery means connected to the gas discharge port via a gas discharge duct, and has a discharge port for molten slag and molten metal at a lower portion, and the gas discharge port and the molten slag and A tuyere capable of independently blowing a combustion-supporting gas and auxiliary fuel between the molten metal outlet and burning and gasifying charcoal generated by dehydration and pyrolysis of waste. An upper blowing lance having at least one stage of tuyeres in the height direction including tuyeres for injecting combustible gas and auxiliary fuel that can be raised and lowered into the furnace at the upper part of the furnace. And further comprising means for measuring the level of the loaded waste, means for measuring the temperature in the vicinity of the tuyere in the middle stage, and means for measuring the temperature of the atmospheric gas in the upper part of the furnace. Waste gasification and melting furnace.

(4) A method for gasifying and melting waste according to the above (3), wherein the method comprises the steps of:
The waste charged into the furnace from the waste charging inlet is subjected to a reaction in each of the following zones, and dust containing energy gas mainly composed of CO and H ₂ and low-boiling heavy metals, molten slag and molten metal. Disposal characterized in that the former is recovered from a gas outlet provided in the upper part of the furnace and separated into energy gas and dust, and the latter is recovered from a molten slag and a molten metal outlet provided in the lower part of the furnace. Method of gasification and melting of materials.

[First Zone] A combustion supporting gas and, if necessary, auxiliary fuel are blown from the lower tuyere, and the carbide generated in the second zone is burned and gasified to generate a reducing gas and to be contained in the carbide. The molten ash and metals are melted to form molten slag and molten metal.

[Second Zone] The supporting gas and auxiliary fuel, if necessary, are blown from the tuyere at the middle stage and / or the upper blowing lance, and the reducing gas generated in the first zone is subjected to secondary combustion to produce waste. The waste charged from the charging inlet is dehydrated and heated to thermally decompose into carbide and hydrocarbon gas, while gasifying low-boiling heavy metals.

[Third Zone] A combustible gas and, if necessary, an auxiliary fuel are blown from an upper tuyere and / or an upper blowing lance, and the hydrocarbon gas generated in the second zone is thermally decomposed to CO and H. Energy gas containing ₂ as a main component, and gaseous low-boiling heavy metals as dust.

(5) A part of the recovered energy gas is directly blown into the third zone of the gasification and melting furnace as a recycle gas, or at least a part of the blown energy gas is burned to emit CO ₂ and H ₂ O. The method for gasifying and melting waste according to the above (2), wherein the gas after generating and containing the waste gas is blown as a recycled gas, or a mixed gas of the recycled gas and oxygen is blown.

(6) Injection of the recycle gas or the mixture gas of the recycle gas and oxygen is performed by using a tuyere provided at an angle θ with respect to a tangent in the circumferential direction of the gasification and melting furnace at 0 ° <θ <90 °. The method for gasifying and melting waste according to the above (5).

The “plural stages” of the “tuples divided into plural stages” in the above (1) are practically three stages, but are not necessarily limited to three stages, and are provided in an auxiliary manner. There may be four or more stages including the tuyere.

The "zone" of the above (2) or (4) is a region in the furnace, which will be described later, and is referred to as a first zone, a second zone and a third zone according to the reaction occurring therein.

The “low-boiling heavy metals” in the above (3) or (4) include mercury (Hg), cadmium (Cd), lead (P
b) In addition, metals such as arsenic (As) and zinc (Zn) which have a high vapor pressure at a temperature of 1200 ° C. or lower or in the vicinity thereof, and chlorides of these metals, that is, HgC
l ₂ , CdCl ₂ , PbCl ₂ , ZnCl ₂ , or oxides of these metals, ie, HgO, CdO, Pb
O, ZnO, etc., or sulfides of these metals, that is, elements designated as environmentally harmful, such as HgS, CdS, PbS, ZnS, and compounds thereof.

The "metals" of the above (1) or (3) refer to valuable metals as described above, and include, for example, aluminum (Al), iron (Fe), copper (Cu), and the like. A metal such as nickel (Ni) and an oxide thereof,
Collected items are generally valued as valuable.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention (the inventions (1) to (6) above) will be described below in detail with reference to the drawings.

FIG. 1 is a schematic vertical sectional view showing an example of the configuration of the waste gasification and melting furnace according to the invention (1), in which the tuyere is divided into three stages in the height direction. Hereinafter, this case will be described as an example.

As shown, waste gasification and melting furnace 1
Is a waste inlet 11- for charging waste at the top.
1 and a gas outlet 3-1 for discharging generated gas. The hopper 11 is installed at the waste loading port 11-1.
-2 and a pusher 10 are attached, and a gas exhaust port 3-1 has a duct 3 for collecting exhaust gas 4.
-2 is attached. A discharge port 9 for discharging the molten slag and the molten metal 13 is provided in the lower part of the furnace.

Between the waste loading port 11-1 on the furnace side wall and the discharge port 9 for molten slag and molten metal, each has a height in a height direction in which the supporting gas and the auxiliary fuel can be independently blown. The tuyeres are divided into stages. That is, in order from the bottom of the furnace, the packed bed 1 mainly composed of carbide generated by dehydrating and heating and thermally decomposing waste.
Tuyere (lower tuyere, hereafter referred to as "primary tuyere 5-1")
) And a tuyere for injecting the combustible gas 7-2 and the auxiliary fuel 6-2 into the packed bed 15 composed mainly of waste in a charged state (middle tuyere, hereinafter referred to as "2 Next tuyere 5-
2)) and the free board 16 has the supporting gas 7-3.
And a tuyere for injecting the auxiliary fuel 6-3 (the upper tuyere, hereinafter referred to as "tertiary tuyere 5-3"). The supporting gas is pure oxygen or a gas containing oxygen, and the auxiliary fuel is a solid fuel such as pulverized coal, a liquid fuel such as heavy oil, or a gas fuel such as natural gas.

Further, a sounding device 17 as a means for measuring the level of the waste charged in the furnace (height level, hereinafter referred to as a raw material layer top level) is provided at the upper part of the furnace. A sounding weight 18 attached to the tip of the device 17 is suspended in the furnace.

A thermocouple 20 for measuring the temperature in the vicinity of the middle tuyere (secondary tuyere 5-2) and the temperature of the atmosphere gas in the upper part of the furnace (ie, free board) Thermocouple 21 for measuring the temperature of the exhaust gas in the space) and a temperature converter 1 for converting the signal of the thermocouple into a temperature.
9 is attached. The temperature in the vicinity of the middle tuyere (secondary tuyere 5-2) refers to the temperature of the second zone corresponding to the secondary tuyere 5-2.

As described above, the gasification and melting furnace of the present invention
This is a vertical, single-furnace gasification and melting furnace. The reason for using the single-furnace method is to simplify the equipment and reduce the equipment cost. Also, in order to suppress heat loss from the furnace body, the one-furnace method is preferable.

In this gasification and melting furnace, the reason why the tuyere was provided in three stages in the height direction of the furnace, the reason why the sounding device 17 was provided, and the thermocouple was attached to a predetermined portion of the furnace side wall. Will be described in conjunction with the waste gasification and melting method of the invention (2) described below.

The method for gasifying and melting waste according to the invention (2) is a method for gasifying and melting waste using the gasification and melting furnace according to the invention (1). Hereinafter, the case of using the gasification and melting furnace shown in FIG. 1 will be described.

First, the waste is put into the hopper 11, pushed into the furnace through the waste inlet 11-1 by the pusher 10, and then into the first zone to the third zone described in detail below.
By the reaction in the zone, the energy gas mainly composed of CO and H ₂ , the molten slag and the molten metal are collected, and the former is recovered from the gas outlet 3-1 provided in the upper part of the furnace, and the latter is provided in the lower part of the furnace. The collected molten slag and molten metal are recovered from the outlet 9.

The furnace has three zones according to the reaction that takes place:
That is, a region where the gasification and melting of carbides occur in order from the bottom of the furnace (first zone), a region where dehydration / pyrolysis of waste occurs (second zone), and a region where gas reforming proceeds (third zone). (See FIG. 1), and the respective areas, that is, the first zone, the second zone, and the third zone
The above-mentioned primary tuyere 5-1, secondary tuyere 5-2 and tertiary tuyere 5-3, which can independently inject the supporting gas and auxiliary fuel necessary for the reaction into the zone, respectively. It is attached. By adopting such a configuration,
It is possible to avoid the hanging and the blow-through (specifically, which is likely to occur when coke is not used as in the method of the present invention) peculiar to the vertical furnace. In addition, the tuyere for supplying the supporting gas and the auxiliary fuel is not limited to the above-mentioned three stages, and in order to supply an amount necessary for the reaction, a plurality of stages are provided in each zone as necessary, Four or more stages may be provided.

In the first zone, a reaction represented by the following equation occurs. This reaction is a reaction in which the carbide (filled bed) formed in the second zone and descending is burned by the oxidizing gas 7-1 blown from the primary tuyere 5-1. It becomes a reducing gas mainly composed of CO at a temperature of 2000 ° C. or higher. In addition, the ash (inorganic oxide) and metals contained in the carbide are melted by the sensible heat to form molten slag and molten metal. The primary tuyere 5-1 may be used if necessary.
Supplies the auxiliary fuel 6-1.

The reducing gas moves to the second zone,
The molten slag and the molten metal are recovered from an outlet 9 at the bottom of the furnace.

C + 1 / 2O ₂ = CO where C: carbide supplied from the second zone O ₂ : oxygen in the combustion supporting gas blown from the primary tuyere, discarded in the second zone The reason why the carbide is gasified and melted in the first zone by dehydrating and pyrolyzing the material to form a packed bed of carbides is that the two-stage method promotes the heating of the carbides, the molten slag and the molten metal. This is because the heat dissipation loss can be effectively suppressed.

In the first zone, it is necessary to completely melt the ash and metals contained in the carbide by the sensible heat of the reducing gas to be generated.
It is preferable to keep the temperature at or above C. For this purpose, the oxygen concentration in the supporting gas is set to 50% by volume or more (hereinafter,% of the gas means volume%), and auxiliary fuel is blown if necessary. In order to smoothly extract the molten slag and the molten metal from the outlet at the bottom of the furnace without causing clogging or the like, limestone is simultaneously charged from above the furnace when the waste is charged into the furnace, or It is preferable to reduce the viscosity of the slag by blowing powdery limestone as a slag-making material from the next tuyere.

In the second zone, reactions represented by the following formulas (1) to (3) occur. The reaction of the formula is the dehydration heating of waste,
This is performed by the sensible heat of the high-temperature reducing gas supplied from the first zone. The reduction gas is also generated by sensible heat generated when the secondary combustion is performed in accordance with the reaction formula of the combustible gas 7-2 blown from the secondary tuyere 5-2. As a result, the organic matter in the waste is thermally decomposed into a hydrocarbon (however, represented as C in the formula and the formula) and hydrocarbon gas according to the formula and the formula. The auxiliary fuel 6-2 is supplied from the secondary tuyere if necessary.

The carbide obtained in this step moves to the first zone, and the hydrocarbon gas moves to the third zone.

[0053] _{H 2 O (liq) = H} 2 O (gas) ··· C p H q O r = r / 2CO 2 + q / nC m H n + (p-r / 2-qm / n) C · _{·· C m H n = n /} 4CH 4 + {m- (n / 4)} C ··· CO + 1 / 2O 2 = CO 2 ··· here, H ₂ O (liq): deposition of the waste moisture C _p H _q O _r: organics C _m H _n in waste: hydrocarbon gas produced by the decomposition of organic substances in waste C: carbides are supplied to the first zone CO: carbides combustion in the first zone CO ₂ generated by the combustion: oxygen in the oxidizing gas blown from the secondary tuyere In this step, if necessary, auxiliary materials (eg, limestone, quicklime, etc.) are added to the waste charged into the furnace. To form a filling layer. That is, the waste is relatively densely packed. By forming such a packed layer of waste, the contact time between solid and gas when a high-temperature gas passes through the layer is prolonged, and thermal efficiency is improved.

The reason why the high-temperature reducing gas is subjected to the secondary combustion is to promote the heating by using the secondary combustion heat in the equation and to control the thermal decomposition temperature to 800 to 1000 ° C.
This secondary combustion heat is much larger than the combustion heat (primary combustion heat) in the above equation, and is effective in replenishing the heat required for dehydration and thermal decomposition of waste. At this time, in order to suppress the sensible heat loss by reducing the amount of generated gas to prevent scattering of waste and to suppress the calorie reduction of the generated gas, the oxygen concentration in the supporting gas should be 50% or more. It is preferred that

In the third zone, the following formula and the reaction represented by the formula occur. These reactions are thermal decomposition reactions (gas reforming reactions) of hydrocarbon gas supplied from the second zone.
Gas with CO and H ₂ as main components (energy gas)
Is obtained. These reactions proceed by the reaction with the combustible gas 7-3 blown from the tertiary tuyere 5-3. The auxiliary fuel 6-3 is supplied from the tertiary tuyere if necessary.

C _m H _n + m / 2O ₂ = mCO + n / 2H ₂ ··· CH ₄ + 1 / 2O ₂ = CO + 2H ₂ ··· Here, C _m H _n : Waste is thermally decomposed in the second zone. the produced hydrocarbon gas CH _4: second zone C _m H _n methane gas generated by thermal decomposition O _2: reaction with oxygen the third zone of the combustion assisting gas blown from the tertiary tuyeres The reaction is performed in such a hollow portion, which is performed in 16 parts of the free board, in order to smoothly advance a gas reforming reaction, which is a reaction between gases. Controlling the atmosphere temperature in the cavity to 800 to 1000 ° C. is preferable because the reforming reaction sufficiently proceeds.

The oxygen concentration in the combustion supporting gas is preferably set to 50% or more. This is because the calorie of the recovered gas is increased so that the gas can be easily used in applications such as power generation in the next process. Further, in order to suppress the generation of dioxins and their precursors, the temperature of the gas is preferably 500 ° C. or higher.

As described above, in the method for gasifying and melting waste according to the invention (2), the reaction gas in the first to third zones is used to produce an energy gas containing CO and H ₂ as main components. Collect the molten slag and molten metal. Therefore, three stages of primary to tertiary tuyeres are required.

Further, the tuyere of each stage must be capable of independently injecting the supporting gas and the auxiliary fuel. The reason is as follows.

First, in the case of the primary tuyere, the amount of C (carbide) involved in the reaction of the formula varies depending on the formula and the degree of progress of the reaction represented by the formula. In addition, if the type of waste changes, the formula and the amount of reaction products represented by the formula naturally change. Therefore, the amount of the supporting gas blown from the primary tuyere must be determined independently of the other steps. The same applies to auxiliary fuel supplied as needed.

Next, the amount of the supporting gas blown from the secondary tuyere is determined by the reaction formula, and the amount of CO in the formula is determined by the reaction formula. Is considered to be linked to However, in fact, it is not necessary to perform secondary combustion on all CO gas generated by the reaction formula. In the second zone, at least heat necessary for dehydration heating of attached moisture in waste and thermal decomposition of organic matter in waste is added. And the atmosphere temperature in the second zone is set to 800 to 1000.
It is only necessary to apply the heat necessary to maintain the temperature in ° C. Therefore, the amount of combustible gas from the secondary tuyere varies greatly depending on the components contained in the waste. That is, the amount of the combustible gas blown from the secondary tuyere must also be determined independently. The same applies to auxiliary fuel.

The amount of the supporting gas blown from the tertiary tuyere is determined by the reaction formula. Since the amount of C _m H _n and CH ₄ is changed by containing component in this case waste, 3
The amount of the supporting gas blown from the next tuyere must also be determined independently. The same applies to the auxiliary fuel.

In the gasification and melting furnace of the invention (1) described above, the tuyeres are provided in three stages, and the combustion supporting gas and the auxiliary fuel can be blown independently of each other. This is for the above reason.

The blowing amount of the supporting gas and the amount of the auxiliary fuel to be supplied as necessary are determined as follows.

When the target of the treatment is, for example, general waste in which different kinds of wastes are mixed, since the component analysis is not usually performed before charging into the furnace, unknown components are burned in the furnace. Or thermal decomposition, and it is practically impossible to predict the amount of generated gas and its components.

Under such conditions, the level of the loaded waste (raw material layer top level) is sequentially measured. This makes it possible to indirectly grasp the change in the thickness of the packed bed in the furnace (the packed bed of waste and the packed bed of carbide). That is, as the amount of combustion increases, the loading of the carbide packed layer formed in the first zone decreases, and the top level of the raw material layer decreases. Therefore, a predetermined raw material layer top level is determined empirically in advance, and then the supporting gas from the primary tuyere and the auxiliary fuel supplied as necessary are blown based on the vertical fluctuation of the raw material layer top level. The amount may be determined. In addition, as a raw material layer top level meter to be used, a sounding device known as a raw material layer top level meter inside a blast furnace in the field of steelmaking is suitable.

Since the packed bed of the waste formed in the second zone exists on the packed bed of the carbide formed in the first zone, the measured top level of the raw material layer is the first zone. And the sum of the respective changes in the second zone. Therefore, it is necessary to distinguish the amount of change between the first zone and the second zone, but the change in the reaction in the second zone can be indirectly grasped by sequentially measuring the temperature change in the second zone. That is, in the second zone, at least heat required for dehydration heating of the adhering moisture in the waste and thermal decomposition of the organic matter in the waste is applied, and the second zone is further heated.
Since it is only necessary to apply heat necessary to maintain the ambient temperature of the zone at 800 to 1000 ° C., the temperature change of the waste in the area of the second zone is sequentially measured, and if it decreases, it is judged that the heat is insufficient. Then, the amount of combustible gas from the secondary tuyere is increased to increase the amount of CO for secondary combustion (the amount of secondary combustion of the CO generated by the reaction formula). Conversely, if the temperature rises, it can be determined that there is a thermal margin, so the amount of the supporting gas from the secondary tuyere may be reduced to reduce the amount of CO to be subjected to secondary combustion. The temperature change of the waste can be regarded as the temperature change of the second zone, and the temperature change of the second zone can be determined, for example, by installing a thermocouple on the surface of the lining brick of the second zone, Can be determined by measuring

As described above, by successively measuring the level value by the raw material layer top level meter and the surface temperature of the lining brick in the second zone, the auxiliary gas to be supplied if necessary and the combustion supporting gas in the first and second zones. Each fuel injection amount can be independently determined.

In the third zone, if the ambient temperature at the outlet of the second zone (on the free board side) is maintained at 800 to 1000 ° C., hydrocarbons in the exhaust gas, especially tar and the like, which cause troubles such as pipe blockage. All hydrocarbons having 5 or more carbon atoms (Cm Hn: m ≧ 5) can be decomposed. Therefore, a thermometer is installed in the freeboard space of the third zone, and the temperature is sequentially measured. When the temperature drops below 800 ° C., the tertiary tuyere provides the supporting gas and, if necessary, the auxiliary fuel. Just blow it. In particular, immediately after the waste is charged into the furnace, the temperatures at the top of the raw material layer in the second zone and the freeboard in the third zone drop sharply, so judging from the temperatures in the second and third zones, In order to decompose the generated hydrocarbons (Cm Hn: m ≧ 5), it is effective to blow a supporting gas and, if necessary, an auxiliary fuel.

According to the waste gasification / melting method of the invention (2), a series of waste gasification / melting, dehydration / pyrolysis and gas reforming steps can be performed without using expensive coke. It can be carried out in one furnace and can be a clean exhaust gas containing no tar or the like.

FIG. 2 is a schematic vertical sectional view showing the structure of an example of the waste gasification and melting furnace of the invention (3).

As shown, the waste gasification and melting furnace 1
Is a waste inlet 11- for charging waste at the top.
1 and a gas outlet 3-1 for discharging generated energy gas and dust accompanying the energy gas. The hopper 11-
2 and a pusher 10, and a hot cyclone (dust collecting means) 25 for collecting energy gas and dust (indicated as exhaust gas 4 in the figure) is provided at a gas outlet 3-1. 2 are attached. The energy gas and the dust pass through the hot cyclone 25 and the energy gas 26
And dust 27. As a dust collecting means, a hot cyclone is inexpensive and is economically preferable, but a dust removing device such as a bag filter may be used.

In the lower part of the furnace, molten slag and molten metal 13
A slag discharge port 9 for discharging slag is provided.

Between the gas discharge port 3-1 and the discharge port 9 for molten slag and molten metal, vanes divided into three stages in the height direction into which the supporting gas and auxiliary fuel can be independently blown are provided. A mouth is provided. This is similar to the case of the waste gasification and melting furnace shown in FIG. 1 described above. In order from the bottom of the furnace, the waste is dehydrated and heated, and the packed bed 14 mainly composed of carbide generated by thermal decomposition is formed. Supporting gas 7
Tuyere (lower tuyere, hereinafter referred to as "primary tuyere 5-1") for injecting -1 and auxiliary fuel 6-1 and a packed bed mainly composed of waste in a charged state 15 is a tuyere for injecting the combustible gas 7-2 and the auxiliary fuel 6-2 into the tuner 15 (the tuyere in the middle stage, hereinafter referred to as "secondary tuyere 5-2")
And a tuyere for injecting the supporting gas 7-3 and the auxiliary fuel 6-3 into the free board 16 (the tuyere at the upper stage,
"Tertiary tuyere 5-3"). The supporting gas is pure oxygen or a gas containing oxygen, and the auxiliary fuel is a solid fuel such as pulverized coal, a liquid fuel such as heavy oil, or a gas fuel such as natural gas. In addition, since the packed bed 15 mainly composed of waste is charged with limestone at the same time as waste to lower the viscosity of the molten slag and molten metal and smoothly discharge the molten slag and the molten metal from the outlet 9 at the lower part of the furnace, some limestone is used. They are mixed.

Further, on the upper part of the waste gasification and melting furnace 1, an upper blowing lance 24-1 capable of injecting the supporting gas 22 and, if necessary, an auxiliary fuel 23, and this lance 24-1 are provided. A lance lifting device 24-2 for raising and lowering is provided.

In the gasification and melting furnace described above, the waste loading port 1
1-1 is installed between the secondary tuyere 5-2 and the tertiary tuyere 5-3, but is not limited to this position. The gasification and melting furnace shown in FIG. As in the case, it may be mounted on the tertiary tuyere 5-3. However, as in this example, the one installed between the secondary tuyere 5-2 and the tertiary tuyere 5-3 is a waste gas in which clean gas after reforming in the third zone falls. As it does not collide with objects, there is little pollution of clean gas and scattering of waste,
desirable.

In this example, three-stage tuyeres are provided between the gas outlet 3-1 and the outlet 9 for the molten slag and the molten metal. It is sufficient that at least one tuyere is provided including a tuyere for burning and gasifying a carbide produced by dehydration and heating and pyrolysis, that is, a primary tuyere attached to a first zone in a furnace. In the case of one stage, the above-described upper lance 24-1 is used, which will be described in an embodiment described later.

Further, in this gasification / melting furnace, as in the case of the waste gasification / melting furnace shown in FIG. Level) is provided. In addition, a thermocouple 20 for measuring the temperature near the middle tuyere (secondary tuyere 5-2) is provided on the furnace side wall,
A thermocouple 21 for measuring the temperature of the atmosphere gas in the upper part of the furnace (that is, the temperature of the exhaust gas in the freeboard space) and a temperature converter 19 for converting a signal of the thermocouple into a temperature are attached. The temperature in the vicinity of the middle tuyere (secondary tuyere 5-2) refers to the temperature of the second zone corresponding to the secondary tuyere 5-2.

The reason why a sounding device is provided in this gasification / melting furnace and a thermocouple is attached to a predetermined portion of the furnace side wall is the same as in the case of the waste gasification / melting furnace shown in FIG. .

As described above, this gasification-melting furnace is also a vertical, single-furnace-type gasification-melting furnace, which can simplify the equipment and reduce the equipment cost. This is a preferable method from the viewpoint of suppressing heat loss. Further, if this gasification and melting furnace is used, as described below, mercury (Hg), cadmium (Cd), lead (P
Harmful low-boiling heavy metals such as b) can be recovered as dust.

The method for gasifying and melting waste according to the invention (4) is a method for gasifying and melting waste using the gasification and melting furnace according to the invention (3). Hereinafter, the case of using the gasification and melting furnace shown in FIG. 2 will be described.

First, as in the case of carrying out the gasification and melting method of the invention (2), the waste is put into the hopper 11-2, and is pushed in by the pusher 10 to push the waste inlet 11-.
Charge from 1 into the furnace. Next, the energy gas mainly composed of CO and H2 is recovered by the reaction in the first to third zones described in detail below. At this time, the dust containing the low-boiling heavy metals is removed together with the energy gas. The gas is recovered from a gas discharge port 3-1 provided at the upper part of the furnace. Further, the obtained molten slag and molten metal are collected from a discharge port 9 of the molten slag and molten metal provided at the lower part of the furnace.

In the furnace, as in the case of the gasification and melting method of the invention (2), there are three regions according to the reaction that takes place, that is, regions where carbide gasification and melting occur in order from the bottom of the furnace (first region). 1 zone 14), a region in which dehydration / pyrolysis of waste and gasification of low-boiling heavy metals occur (second zone 15), and a region in which gas reforming proceeds. It is divided into regions (third zone 16) where dust containing low-boiling heavy metals to be discharged is present (see FIG. 2). Each of the above zones can be independently blown with the supporting gas and auxiliary fuel required for the reaction.
The next tuyere 5-1, the second tuyere 5-2, and the third tuyere 5-3 are attached correspondingly, and further, the upper blowing lance 24-
1 is attached. By adopting such a configuration, the organic matter contained in waste can be efficiently gasified to recover energy gas that can be used as fuel, and the low-boiling heavy metals contained in these waste can be efficiently recovered as dust. At the same time, the ash and valuable metals contained in these wastes can be efficiently recovered as molten slag and molten metal, respectively. In addition, it is possible to avoid the hanging of a shelf and the occurrence of blow-through, which are peculiar to a vertical furnace.

In the first zone, a reaction represented by the following equation occurs as in the case of the gasification melting method of the invention (2). This reaction is a reaction in which the carbide (filled bed) that has been formed in the second zone and descends is burned by the supporting gas 7-1 blown from the primary tuyere 5-1. The carbide is burned and gasified. , A reducing gas mainly composed of CO at 2000 ° C. or higher. In addition, the ash (inorganic oxide) and valuable metals contained in the carbide are melted by the sensible heat to form molten slag and molten metal. In addition, the auxiliary fuel 6-1 is supplied from the primary tuyere 5-1 if necessary.

The reducing gas moves to the second zone,
The molten slag and the molten metal are recovered from an outlet 9 at the bottom of the furnace.

C + 1 / 2O2 = CO where C: carbide supplied from the second zone O2: oxygen in the supporting gas blown from the primary tuyere Dehydration / pyrolysis to form a packed bed of carbides and gasification and melting of the carbides in the first zone is, like the above, divided into two stages in this way to promote heating of the carbides, molten slag and melting. This is because heat loss from metal can be effectively suppressed.

In the first zone, it is necessary to completely melt the ash and valuable metals contained in the carbide by the sensible heat of the reducing gas to be generated.
It is preferable to keep the temperature at 00 ° C. or higher. For this purpose, the oxygen concentration in the supporting gas is set to 50% or more, and auxiliary fuel is blown if necessary. In order to discharge the molten slag and the molten metal smoothly from the discharge port at the bottom of the furnace without causing clogging or the like, limestone is simultaneously charged from above the furnace when the waste is charged into the furnace, or It is preferable to reduce the viscosity of the slag by blowing powdery limestone as a slag-making material from the next tuyere.

In the second zone, as in the case of the gasification melting method of the invention (2), the reactions represented by the following formulas (1) to (3) occur. Gasification of contained chlorine and gasification of low boiling heavy metals or reaction with chlorine occurs.

H2O (liq) = H2O (gas) ... CpHqOr = r / 2CO2 + q / nCmHn + (pr-2-qm / n) C ... CmHn = n / 4CH4 + {M- (n / 4)} C CO + 1 / 2O2 = CO2 where H2O (liq): adhering moisture in waste Cp Hq Or: organic matter in waste Cm Hn: waste Hydrocarbon gas generated by decomposition of organic matter in the material C: Carbide supplied to the first zone CO: CO O2 generated by burning of the carbide in the first zone: Injected from the secondary tuyere and / or upper blowing lance The oxygen-type reaction in the combustible gas is performed by sensible heat of the high-temperature reducing gas supplied from the first zone by dehydration heating of the waste. Further, this reducing gas is supplied to the combustion supporting gas 7-2 and / or the upper blowing lance 24-1 injected from the secondary tuyere 5-2.
This is also performed by sensible heat generated when performing secondary combustion according to the reaction formula by the combustible gas 22 blown from the air. As a result, the organic matter in the waste is thermally decomposed into a hydrocarbon (however, represented as C in the formula and the formula) and hydrocarbon gas according to the formula and the formula. If necessary, auxiliary fuel is supplied from the secondary tuyere and / or the upper lance.

The blowing of the flammable gas may be performed using only the secondary tuyere or only the upper blowing lance, whereby the dewatering and heating of the waste can be performed. However, if the secondary tuyere and the upper blowing lance are used at the same time, the combustion supporting gas can be uniformly blown into the second zone, so that the dewatering and heating of the waste can be efficiently performed.

The carbide obtained in this step moves to the first zone, and the hydrocarbon gas moves to the third zone.

In the second zone, the following sensible heat is generated by the sensible heat of the high-temperature reducing gas supplied from the first zone or in addition to the sensible heat generated during the secondary combustion according to the reaction formula. The reactions shown in Formulas -1 to -3 occur. The above-mentioned gasification of chlorine contained in the waste and gasification of heavy metals having a low boiling point or reaction with chlorine. That is, the chlorine contained in the waste is −1
And -2 to produce chlorine gas and hydrogen chloride gas. On the other hand, heavy metals having a low boiling point in wastes are gasified as they are by the formula (1), or chlorides of heavy metals having a low boiling point are generated as shown in the formulas (2) and (-3). In general, when chloride is used, it is very easy to evaporate.

2Cl = Cl2 (gas)... -1 2Cl + H2O (gas) = 2HCl (gas)... -2 M = M (gas)... -1 M (gas) + Cl2 (gas) = MCl2 (Gas) ...- 2 M (gas) + 2HCl (gas) = MCl2 (gas) + H2 ...- 3 where Cl: chlorine in waste M: low boiling heavy metal in waste (for example, Hg , Cd, P
b etc.) M (gas): gasification product of low boiling point heavy metal MCl2 (gas): chloride of low boiling point heavy metal In this step, as in the case of the gasification melting method of the invention (2), the furnace If necessary, auxiliary materials (eg, limestone, quick lime, etc.) are added to the waste charged into the inside to form a packed layer. That is, the waste is relatively densely packed. By forming such a packed layer of waste, the contact time between solid and gas when a high-temperature gas passes through the layer is prolonged, and thermal efficiency is improved.

The secondary combustion of the high-temperature reducing gas is performed by using the secondary combustion heat of the formula to promote the heating, controlling the thermal decomposition temperature of the organic substance to 800 to 1400 ° C., and having a low boiling point. This is for gasifying heavy metals.

The reason why the thermal decomposition temperature is set to 800 to 1400 ° C. is to promote the gasification of organic substances by thermal decomposition and to completely gasify low-boiling heavy metals. Since the heat of secondary combustion is much larger than the heat of combustion (primary heat of combustion) in the above equation, it is possible to sufficiently supplement the heat necessary for dehydration / pyrolysis of waste and gasification of low-boiling heavy metals. it can. In addition, at this time, in order to suppress the sensible heat loss by reducing the amount of generated gas, and to suppress a decrease in calories of the generated gas,
It is preferable that the oxygen concentration in the supporting gas be 50% or more. Further, when the amount of generated gas is reduced, scattering of waste can be prevented and the concentration of low boiling heavy metals contained in dust can be increased. Therefore, the oxygen concentration in the combustion supporting gas is increased to 50% or more. Is preferred.

In the third zone, as in the case of the gasification and melting method of the invention (2), the following formulas and the reaction represented by the formulas occur.

Cm Hn + m / 2O2 = mCO + n / 2H2 CH4 + 1 / 2O2 = CO + 2H2 where CmHn: hydrocarbon gas generated by thermal decomposition of waste in the second zone CH4: second Methane gas generated by the thermal decomposition of Cm Hn in the zone O2: Oxygen in the combustion supporting gas blown from the tertiary tuyere and / or top blowing lance These reactions are based on the hydrocarbon gas supplied from the second zone. By the thermal decomposition reaction (gas reforming reaction), a gas (energy gas) containing CO and H2 as main components is obtained. These reactions are carried out by the supporting gas 7-3 blown from the tertiary tuyere 5-3.
The reaction proceeds with the combustion supporting gas 22 blown from the upper blowing lance 24-1. If necessary, auxiliary fuel is supplied from the tertiary tuyere and / or the upper blowing lance.

The blowing of the supporting gas may be performed using only the tertiary tuyere or only the upper blowing lance, whereby it is possible to cause the above formula and the reaction shown by the formula. However, if the tertiary tuyere and the upper blowing lance are used at the same time, the combustion supporting gas can be evenly and uniformly blown to the free board in the third zone, so that the reaction represented by the expression and the expression can be performed efficiently. be able to.

The reaction in the third zone is free board 1
The reaction is performed in six cavities. The reason why the reaction is performed in such a cavity is to smoothly perform a gas reforming reaction, which is a reaction between gases. The atmosphere temperature in the cavity is 800 to 1400
It is preferable to control the temperature to ° C., because the reforming reaction sufficiently proceeds. More preferably, it is 1000-1200 degreeC.

From the viewpoint of suppressing the production of dioxins and their precursors such as chlorobenzene and chlorophenol, the ambient temperature is preferably 500 ° C. or higher, and furthermore, dioxins, chlorobenzene, chlorophenol and the like. 9 to completely decompose
The temperature is more preferably set to 00 ° C. or higher.

It is preferable that the oxygen concentration in the supporting gas is 50% or more. This is because the calorie of the recovered gas is increased so that the gas can be easily used in applications such as power generation in the next process.

In the above-described example, a gasification and melting furnace provided with three-stage tuyeres corresponding to each zone and an upper blowing lance is used. As described above, at least one tuyere is provided. Just do it. This is because the supply of the supporting gas and the auxiliary combustion to the second zone and the third zone can be performed by the upper blowing lance, so that the one-stage tuyere may be attached to a portion corresponding to the first zone.

As described above, in the method for gasifying and melting waste according to the invention (4), the reaction in the first to third zones causes an energy gas containing CO and H2 as main components and a low boiling point. Collect dust containing heavy metals, molten slag and molten metal. Therefore, at least one tuyere and an upper blowing lance are required.

Further, at least one of the tuyere and the upper blowing lance must be capable of independently blowing the supporting gas and the auxiliary fuel. The reason is as follows. It is assumed that the tuyere is attached to each zone.

First, the case of the primary tuyere is the same as the case of the gasification melting method of the invention (2). That is,
The amount of C (carbide) involved in the reaction of the formula varies depending on the formula and the degree of progress of the reaction represented by the formula. In addition, if the type of waste changes, the formula and the amount of reaction products represented by the formula naturally change. Therefore, 1
The amount of the supporting gas blown from the next tuyere must be determined independently of other processes. The same applies to auxiliary fuel supplied as needed.

Next, the amount of the combustible gas blown from the secondary tuyere and / or the upper blowing lance is determined by the reaction formula, and the CO amount in the formula is determined by the reaction formula. It is considered that it is linked to the amount of supporting gas to be blown. However, in fact, it is not necessary to secondarily combust all the CO gas generated by the reaction formula. In the second zone, at least dehydration heating of adhering moisture in waste and thermal decomposition of organic matter in waste and low boiling point heavy metal Heat required for gasification is added, and the ambient temperature of the second zone is further increased to 800 to 140.
It is only necessary to apply the heat necessary to keep it at 0 ° C. Therefore, the amount of combustible gas from the secondary tuyere and / or the upper blowing lance greatly changes depending on the components contained in the waste. That is, the amount of the supporting gas blown from the secondary tuyere and / or the upper lance must also be determined independently. The same applies to auxiliary fuel.

The ratio of the supporting gas or auxiliary fuel blown from the secondary tuyere and the upper blowing lance is preferably in the range of the following formulas. This is because a synergistic effect cannot be exerted if the ratio is out of this range and either one is too small or too large.

[0108]

(Equation 1)

The amount of the supporting gas blown from the tertiary tuyere and / or the upper blowing lance is determined by the reaction formula. In this case as well, the amount of Cm Hn and CH4 produced varies depending on the components contained in the waste. Therefore, the amount of the supporting gas blown from the tertiary tuyere and / or the upper lance must be determined independently. No. The same applies to the auxiliary fuel.

It is preferable that the ratio of the supporting gas or auxiliary fuel blown from the tertiary tuyere and the upper blowing lance be in the range of the following equations, respectively, as in the case of the secondary tuyere and the upper blowing lance. This is because a synergistic effect cannot be exerted if the ratio is out of this range and either one is too small or too large.

[0111]

(Equation 2)

The amount of the blowing of the supporting gas and the amount of the auxiliary fuel to be supplied as required are determined as follows. Basically, it is the same as the case of the gasification melting method of the invention (2).

When the object to be treated is, for example, general waste in which different types of waste are mixed, since the component analysis is not usually performed before charging into the furnace, unknown components are burned in the furnace. Or thermal decomposition, and it is practically impossible to predict the amount of generated gas and its components.

Under such conditions, the level of the loaded waste (the top level of the raw material layer) is sequentially measured. This makes it possible to indirectly grasp the change in the thickness of the packed bed in the furnace (the packed bed of waste and the packed bed of carbide). That is, as the amount of combustion increases, the loading of the carbide packed layer formed in the first zone decreases, and the top level of the raw material layer decreases. Therefore, a predetermined raw material layer top level is determined empirically in advance, and then the supporting gas from the primary tuyere and the auxiliary fuel supplied as necessary are blown based on the vertical fluctuation of the raw material layer top level. The amount may be determined. As a raw material layer top level meter to be used, a sounding device known as a raw material layer top level meter inside a blast furnace in the field of steelmaking is suitable, but an RI (radioisotope) method or the like is generally effective. This method is known, and this method can be applied.

By the way, since the packed bed of waste formed in the second zone exists on the packed bed of carbide formed in the first zone, the measured top level of the raw material layer is the first zone. And the sum of the respective changes in the second zone. Therefore, it is necessary to distinguish the amount of change between the first zone and the second zone, but the change in the reaction in the second zone can be indirectly grasped by sequentially measuring the temperature change in the second zone. That is, in the second zone, at least heat required for dehydration heating of adhering moisture in the waste, thermal decomposition of the organic matter in the waste and gasification of the low-boiling heavy metal is added, and the atmospheric temperature of the second zone is raised to 80 ° C.
Since it is only necessary to apply the heat necessary to maintain the temperature at 0 to 1400 ° C., the temperature change of the waste in the area of the second zone is sequentially measured. The amount of CO to be secondary-combusted (the amount of secondary combustion of CO generated by the reaction formula) is increased by increasing the amount of the supporting gas from the mouth and / or the upper blowing lance. Conversely, if the temperature rises, it can be determined that there is a thermal margin, so reduce the amount of the supporting gas from the secondary tuyere and / or the upper blowing lance to reduce the amount of CO to be secondary-combusted. I just need. In addition,
The temperature change of the waste can be regarded as the temperature change of the second zone, and the temperature change of the second zone is as follows.
For example, it can be determined by installing a thermocouple on the surface of the lining brick in the second zone and measuring the surface temperature.

As described above, by successively measuring the level value by the raw material layer top level meter and the surface temperature of the lining brick in the second zone, the auxiliary gas to be supplied if necessary and the supporting gas in the first and second zones Each fuel injection amount can be independently determined.

In the third zone, if the ambient temperature at the outlet of the second zone (on the free board side) is maintained at 800 to 1400 ° C., hydrocarbons in the exhaust gas, especially tar and the like which cause troubles such as pipe clogging. All hydrocarbons having 5 or more carbon atoms (Cm Hn: m ≧ 5) can be decomposed. It is also necessary for complete decomposition of dioxins and their precursors such as chlorobenzene and chlorophenol. Therefore, a thermometer is installed in the freeboard space of the third zone, and the temperature is sequentially measured. When the temperature drops below 800 ° C., the combustion supporting gas is supplied from the third tuyere and / or the upper blowing lance. If necessary, auxiliary fuel may be injected.
In particular, immediately after the waste is charged into the furnace, the temperatures at the top of the raw material layer in the second zone and the free board in the third zone rapidly decrease, and thus, judging from the temperatures in the second and third zones, Hydrocarbons generated (Cm Hn: m ≧ 5)
It is effective to inject a supporting gas and, if necessary, an auxiliary fuel in order to decompose or dioxins.

According to the gasification and melting method of the invention (4), a series of steps of gasification and melting of waste, dehydration / pyrolysis, and gas reforming can be performed in one furnace without using expensive coke. A clean exhaust gas that is implemented and does not contain tar, dioxins, or the like can be obtained. Note that dust containing low-boiling heavy metals is contained in the exhaust gas, and the dust and energy gas can be separated by a dust removing device (dust collecting means) such as a hot cyclone provided outside the furnace.

For collecting fine dust which is difficult to collect even with a hot cyclone, washing with water is effective. The dust separated and recovered by the hot cyclone or water treatment contains heavy metals having a low boiling point, and thus can be concentrated through a treatment step using an alkali or an acid. Known techniques can be applied to the treatment using the hot cyclone and the cleaning treatment using water.

(5) The method for gasifying and melting waste according to the invention according to (2), wherein a part of the recovered energy gas is directly supplied to the third zone of the gasification and melting furnace. It is blown as a recycle gas or burns at least a part of the blown energy gas to produce CO2 and H2O, and to produce CO2 and H2O,
Alternatively, a gas containing either one of them is blown as a recycled gas, or a mixed gas of these recycled gas and oxygen is blown.

FIG. 3 is a diagram showing a configuration of an example of a waste gasification and melting furnace for carrying out the present invention. This gasification / melting furnace has the same configuration as the gasification / melting furnace shown in FIG. 1 described above, but as shown, energy gas blown into the third zone (also exhaust gas discharged from the furnace).
Exhaust gas combustion chamber 28 for burning at least a part of
And a tertiary tuyere 5-3 for blowing the combustible gas 7-3 and the auxiliary fuel 6-3 into the free board 16 and for blowing a part of the recovered energy gas as a recycle gas.

In order to carry out the method of the invention of (5) using this gasification and melting furnace, as in the case of carrying out the gasification and melting method of the invention of (2), first, waste is put into the hopper 11. And push it in with pusher 10 to insert waste
Charge from 1 into the furnace. Next, the first gasification melting furnace
By the reaction in the zone to the third zone, the energy gas mainly composed of CO and H2, the molten slag and the molten metal are recovered, and the former is recovered from the gas outlet 3-1 provided in the upper part of the furnace. At this time, a part of the recovered energy gas (exhaust gas) is converted into a recycled gas 7-4 or 7-
5 is blown into the third zone of the gasification and melting furnace. The molten slag and the molten metal are recovered from an outlet 9 provided at the lower part of the furnace.

The reactions in the first zone and the second zone are the same as in the case of carrying out the gasification melting method of the invention (2).

However, in the third zone, the above-mentioned equation and the reaction shown by the equation occur, and the recycle gas or the mixed gas of the recycle gas and oxygen is blown. And-
The reaction of 3 occurs. In addition, as described above, the recycled gas means that the recovered energy gas itself or at least a part thereof is burned to generate CO2 and H2O, and that CO2 and H2O or one of them is contained. Refers to gas.

Cm Hn + m / 2O2 = mCO + n / 2H2 CH4 + 1 / 2O2 = CO + 2H2 where CmHn: hydrocarbon gas generated by thermal decomposition of waste in the second zone CH4: second Methane gas generated by thermal decomposition of Cm Hn in the zone O2: Oxygen in the supporting gas blown from the tertiary tuyere Cm Hn + mCO2 = 2mCO + n / 2H2 ... -2 Cm Hn + mH2 O = mCO + {m + (n / 2)} H2... -3 CH4 + H2 O = CO + 3H2... -3 where CO2 is in the recycled gas blown from the tertiary tuyere 5-3. (That is, CO2 generated in the second zone or CO2 generated by combustion of at least a part of the energy gas) H2 O: blown from the third tuyere 5-3 H2 O in the recycled gas injected (that is, H2 generated in the second zone)
O, or H2 O generated by combustion of at least a part of the energy gas with H2 O) That is, by blowing a recycle gas or a mixture gas of a recycle gas and oxygen, As a result, the above-mentioned reactions from -2 to -3 occur, and the pyrolysis reaction of hydrocarbon gas generated by the pyrolysis reaction of waste, particularly a hydrocarbon gas having a high boiling point and existing as a liquid at room temperature, is promoted, and And H
It is reformed into a gas containing 2 as a main component (energy gas).

As the recycled gas, as shown in FIG. 3, a part of the recovered energy gas may be directly blown into the third zone as a recycled gas 7-4, or a part of the energy gas may be discharged into the exhaust gas combustion chamber. 28
After the gas is guided to burn at least a part of the gas, the gas may be blown as a recycled gas 7-5. When the former method is used, CO2 and H2 O generated in the second zone are contained in the recycle gas. When the latter method is used, CO2 and / or H2O generated by combustion in the exhaust gas combustion chamber 28 are further added. Alternatively, H2 O is also contained, and these components contribute to the above-mentioned thermal decomposition reaction of the hydrocarbon gas of -2 to -3.

Furthermore, a mixed gas obtained by adding oxygen to the recycled gas may be blown into the third zone. in this case,
In addition to the thermal decomposition of hydrocarbon gas by CO2 and H2O contained in the recycle gas, oxygen is contained in a large amount, and this oxygen promotes the above reaction, and the thermal decomposition reaction of hydrocarbon gas is further promoted. Promoted.

The proportion of oxygen added to the recycle gas is not particularly limited. However, in order to suppress the generation of CO 2 and H 2 O, m of hydrocarbon (Cm Hn) generated by thermal decomposition is controlled.
/ 2 or less is preferable.

The method for gasifying and melting waste according to the invention (6) is characterized in that, in the method (5), the recycled gas or the mixed gas of the recycled gas and oxygen is blown into the gasification and melting furnace. As shown in FIG. 4, this method is performed using a tuyere 5-3 installed at an angle θ with respect to a circumferential tangent of the gasification and melting furnace 1 at 0 ° <θ <90 °. In other words, instead of blowing vertically to the furnace wall,
It blows diagonally.

As a result, the mixing of the hydrocarbon gas generated by the thermal decomposition reaction of the waste, especially the hydrocarbon gas having a high boiling point and existing as a liquid at room temperature, and the recycled gas blown into the furnace are promoted, The gas decomposition reaction (gas reforming reaction) is promoted.

According to the waste gasification and melting method (5) or (6), hydrocarbon gas generated by the thermal decomposition reaction of waste, particularly hydrocarbon gas having a high boiling point and existing as a liquid at room temperature, is used. Since the thermal decomposition reaction is promoted, C
Recovery efficiency of a gas (energy gas) containing O and H2 as main components can be improved.

[0132]

【Example】

(Example 1) A gasification melting test of waste was performed using a vertical furnace having the configuration shown in FIG. In addition, the dimension of each part of a vertical furnace, the number of tuyere and other attachment parts, and their arrangement are as follows.

Dimensions Furnace diameter: 0.5 m (furnace inner diameter after brick lining) Furnace height: 2.7 m (however, height from furnace bottom to furnace top after brick lining) Furnace from primary tuyere Height from furnace bottom to secondary tuyere: 1.1 m Height from furnace bottom to tertiary tuyere: 1.9 m Position of thermocouple in second zone: 1.5 m (The position of the thermocouple in the second zone means the height of the thermocouple attached to the surface of the brick in the second zone from the furnace bottom.) The position of the thermocouple in the third zone: 1.7 m (No. The position of the thermocouple in the three zones is the height of the thermocouple installed in the freeboard space from the furnace bottom.) Quantity Primary tuyere: 3 Secondary tuyere: 3 Tertiary tuyere : 3 Molten slag and molten metal outlet: 1 Sounding device (raw material layer top level meter): 1 Sounding weight: 1 2nd zone thermocouple: 3 pieces 3rd zone thermocouple: 3 pieces Arrangement Primary tuyere: Evenly spaced every 120 degrees in the circumferential direction Secondary tuyere: Evenly spaced every 120 degrees in the circumferential direction Tertiary feather Mouth: Equally spaced every 120 degrees in the circumferential direction Molten slag and molten metal outlet: Furnace bottom end Sounding device: Center of the furnace Thermocouple in the second zone: Equally spaced in the circumferential direction every 120 degrees Thermoelectric in the third zone Pair: Equal intervals every 120 degrees in the circumferential direction The wastes used in the above test were three types of mixed general municipal solid waste and waste plastic (samples 1, 2 and 3), each per 1 kg of waste. 5718kca
1, 3506 kcal and 1506 kcal.

Table 1 shows the composition of these wastes, Table 2 shows the composition of the auxiliary material (limestone) used, and Table 3 shows the composition of the auxiliary fuel (pulverized coal) used. The size of the waste was 10 to 100 mm.

[0135]

[Table 1]

[0136]

[Table 2]

[0137]

[Table 3]

Limestone used as an auxiliary material is 10 to 5
It was a lump of 0 mm. The pulverized coal used as the auxiliary fuel was a powdery material of 3 mm or less that had been dried in advance.

The combustible gas blown from the primary tuyere, the secondary tuyere and the tertiary tuyere is a gas based on oxygen and slightly mixed with nitrogen. Table 4 shows their flow rates (the flow rates of oxygen and nitrogen, respectively). In the table,
Primary means primary tuyere. The same applies to the second and third orders.

The test conditions and results are shown in Table 4. In the table, the conditions are the conditions under which this test was performed (steady state), and were determined for each of samples 1, 2 and 3 according to the following procedures (1) to (8). In the test, sample 1 was first charged into the furnace and
The sample was processed under the conditions shown in the column of sample 1, and then changed to sample 2 and processed under the same conditions as shown in the column of sample 2, and further changed to sample 3 and shown in the column of sample 3. Processing was performed under the conditions. The processing time of each sample was 24 hours, and the amount of waste during that time was 1 ton (3 tons in total) for each sample.

(Procedure for Setting Processing Conditions) (1) The composition of the waste initially charged (here, the sample 1) was determined by analyzing the composition in advance. This is necessary to determine the approximate value of the amount of oxygen to be blown, and also to determine the amount of limestone to be charged as a slag-making material. In this test, the amount of limestone was adjusted such that the fluidity of the molten slag was slag basicity considered to be the best (that is, slag basicity = 1.0).

(2) The gasification and melting furnace was heated in advance by a burner or the like, so that the waste was ignited even at room temperature where the combustion supporting gas blown from the tuyere was not heated.

(3) The waste was charged into a furnace and piled up to a sounding height of 1.5 to 1.7 m. The sounding height means the height from the furnace bottom to the top of the raw material layer.

(4) After gradually flowing oxygen gas from the primary tuyere, the outlets for the molten slag and the molten metal were opened.

(5) During the test, the top level of the raw material layer decreased with the burning of the waste, so that the level was 1.5 to 1.7.
Raw materials (waste and limestone) to maintain in the range of m
Were sequentially charged. In the steady state, the input speed of waste was always set at 40 kg / h.

(6) The temperature measured by the thermocouple attached to the surface of the lining brick in the second zone and the thermocouple attached to the free board space in the third zone is always maintained at 800 to 1000 ° C. The primary tuyere, 2
The amount of oxygen gas blown from the next tuyere and the third tuyere was adjusted.

That is, the unloading speed is high and the second
When the temperature in the zone and the zone in the third zone exceeded 1000 ° C., the oxygen gas from the primary tuyere was reduced.
Conversely, if the temperature of the second zone is lower than 800 ° C., 2
Oxygen gas was blown from the next tuyere. When the temperature of the third zone was lower than 800 ° C., pulverized coal was blown together with oxygen gas from the third tuyere. In this case, CO in the exhaust gas can be burned only by blowing oxygen gas from the tertiary tuyere, so that a predetermined temperature rise is possible. Charcoal was used.

(7) The temperatures of the molten slag and the molten metal are measured (this measurement has been conventionally performed), and a predetermined temperature (at least a temperature at which the molten slag and the molten metal do not solidify) is considered. Temperature range (1
400-1600 ° C.).
Pulverized coal was blown from the primary tuyere. In the case where the sample 3 corresponds to the case, when the calorific value of the waste itself is small, it is necessary to supply the auxiliary fuel from the primary tuyere.

(8) By repeating the above (5) to (7), it is possible to derive the optimum amount of the supporting gas and auxiliary fuel to be blown (ie, the amount shown in the condition column of Table 4). did it. In addition, even when the sample was changed (from sample 1 to sample 2 and from sample 2 to sample 3), it was possible to appropriately cope with the case.

The results obtained in the above tests are shown in the column of results in Table 4. The unit is the amount per ton of waste. In Samples 2 and 3 in Table 4, only oxygen gas was blown in the second zone, and the temperature of the second zone was controlled at 800 to 1000 ° C by utilizing the heat of reaction caused by the secondary combustion of the reducing gas. The secondary combustion rates at this time were 34% and 84% for Samples 2 and 3, respectively. Here, the secondary combustion rate is a value calculated by the following equation.

Secondary combustion rate = ｛% CO 2 / (% CO +% C
O2)｝ × 100 Here,% CO: CO% in the second zone% CO2: CO2% in the second zone Although not described in Table 4, pulverized coal is blown from the secondary tuyere together with oxygen gas. By using the heat of combustion, the temperature of the second zone can be increased to 800 to 1000 ° C.
It was possible to control.

As indicated, a high calorie energy gas containing CO and H2 as main components (indicated as exhaust gas in the table), a molten metal containing Fe as a main component, and a molten slag could be recovered. . Also, hydrocarbons in exhaust gas,
In particular, Cm Hn (m
Hydrocarbons such as ≧ 5) had completely negligible concentrations.

[0153]

[Table 4]

<Comparative Example> For comparison, a waste gasification melting test was performed using the same furnace as that used in the examples. However, as shown in the condition column of Table 5, the amount of the supporting fuel gas and the amount of the auxiliary fuel blown from the primary tuyere, the secondary tuyere and the tertiary tuyere are the same (the total amount is the same as in the example). The height of the sounding, the surface temperature of the lining brick in the second zone, and the temperature of the freeboard space were sequentially measured. Based on the data, the amount of the supporting gas and the amount of the auxiliary fuel from each tuyere were measured. Did not change.

The results are shown in the column of results in Table 5. As is evident from this result, under the same waste input rate,
The level of the top of the raw material layer (that is, the sounding height) fluctuated greatly, and was 1.0 to 2.2 m. Further, the temperature fluctuation in the second zone and the third zone is large, and
200 ° C was indicated.

The reason why both the level and the temperature at the top of the raw material layer fluctuated greatly is that the oxygen required for each of the first to third zones and the heat supplied by the reaction with the oxygen were not supplied. is there. The reason why the temperature deviated extremely to the low temperature side is that the level at the top of the raw material layer was extremely high at 2.2 m. Conversely, the reason for shifting to the high temperature side is that the level at the top of the raw material layer is extremely low at 1.0 m. Furthermore, since the oxygen and fuel required for the first zone were insufficient, the temperature of the molten slag and the molten metal shifted to a low temperature side, the dispersion thereof was large, and the discharge was unstable.

Further, since the concentration of hydrocarbons contained in the exhaust gas, particularly hydrocarbons such as Cm Hn (m ≧ 5), which causes pipe clogging, is high, a clean gas that can be directly recovered as an energy gas is obtained. Was not obtained. Moreover, the calories of the exhaust gas excluding Cm Hn (m ≧ 5) were about 20 to 30% lower than those of the example.

[0158] Such a situation was observed in all of the samples 1 to 3, and it was also extremely difficult to take appropriate measures when the sample was changed.

[0159]

[Table 5]

(Example 2) Using a vertical furnace (gasification and melting furnace) having the structure shown in FIG. 2 and simultaneously using the primary tuyere to tertiary tuyere and the upper blowing lance, Was subjected to a gasification melting test. In addition, the dimension of each part of a vertical furnace, the number of tuyere and other attachment parts, and their arrangement are as follows.

Dimensions Furnace diameter: 0.5 m (however, furnace inner diameter after brick lining) Furnace height: 2.0 m (however, height from furnace bottom to furnace top after brick lining) Furnace bottom to primary tuyere Height: 0.3 m Height from furnace bottom to secondary tuyere: 0.6 m Height from furnace bottom to tertiary tuyere: 1.6 m Upper lance outer diameter: 50 mmφ Upper lance hole: Central hole: 1 hole for pulverized coal + carrier gas injection × 3φ × 0 degrees (= vertical direction) Side hole: for oxygen + nitrogen gas injection 3 holes × 5φ × 10 degrees (= tilted 10 degrees to vertical direction) Side holes are arranged at 120 degree intervals around the center hole. Height from furnace bottom to lance tip: Standard 1.8m (but variable up and down) Position of thermocouple in second zone: 0.9m (in second zone) (The position of the thermocouple means the height of the thermocouple attached to the surface of the lining brick in the second zone from the bottom of the furnace.) Position of thermocouple in zone 3: 1.1 m (The position of thermocouple in zone 3 refers to the height of the thermocouple installed in the freeboard space from the furnace bottom.) Quantity Primary tuyere: 3 secondary tuyere: 3 tertiary tuyere: 3 upper blowing lance: 1 outlet for molten slag and molten metal: 1 sounding device (raw material layer top level meter): 1 second zone Thermocouples: 3 Thermocouples in the third zone: 3 Arrangement Primary tuyere: equidistant every 120 degrees in the circumferential direction Secondary tuyere: equidistant every 120 degrees in the circumferential direction Tertiary tuyere: circumferential At equal intervals of every 120 degrees Top blowing lance: Furnace center Molten slag and molten metal outlet: Furnace bottom end Sounding device: Between top blowing lance and side wall Thermocouple in second zone: Every 120 degrees in the circumferential direction Equal spacing of the third zone Thermocouples: Equal spacing every 120 degrees in the circumferential direction Disposal used in the above test Things in general three types of municipal solid waste (designated as Sample 4, 5 and 6), for each drying degree are different, 3408Kca per waste 1kg
1, 2518 kcal and 1628 kcal with a low heat generation reference.

Table 6 shows the composition of these wastes. The size of the waste was 10 to 100 mm.

[0163]

[Table 6]

The auxiliary material (limestone) and auxiliary fuel (pulverized coal) used were the same as those used in Example 1 and had the compositions shown in Tables 2 and 3, respectively. The limestone was a lump of 10 to 50 mm, and the pulverized coal was a powder of 1 mm or less that had been dried in advance.

The combustion supporting gas blown from the primary tuyere, the secondary tuyere, the tertiary tuyere, and the upper blowing lance is a gas based on oxygen and slightly mixed with nitrogen. Table 7 shows the flow rates (the respective flow rates of oxygen and nitrogen).
In the table, primary means primary tuyere. Secondary, 3
The same applies to the following.

[0166]

[Table 7]

Table 7 shows the conditions under which this test was performed (steady state). Samples 4, 5 and 6 were determined according to the following procedures (1) to (8). In addition,
In the test, first, sample 4 was charged into the furnace and treated under the conditions shown in the column of sample 4 in Table 7, and then changed to sample 5 and the conditions shown in the column of sample 5 were also changed. And the sample was changed to Sample 6 and processed under the conditions shown in the column of Sample 6. The processing time of each sample was 24 hours, and the amount of waste during that time was 1 ton (3 tons in total) for each sample.

(Procedure for Setting Processing Conditions) (1) The composition of the waste initially charged (here, sample 4) was determined by previously analyzing the composition. This is necessary in order to determine the approximate value of the oxygen injection amount serving as a base, and also to determine the amount of limestone to be charged as a slag-making material. In addition, the amount of limestone is the slag basicity that the fluidity of molten slag is considered to be the best (that is,
1.0).

(2) The gasification and melting furnace was heated by a burner or the like in advance so that waste gas was ignited even at room temperature where the combustion supporting gas blown from the tuyere was not heated.

(3) The waste was charged into a furnace and piled up to a sounding height of 0.9 to 1.1 m.

(4) After gradually flowing oxygen gas from the primary tuyere, the outlets for the molten slag and the molten metal were opened.

(5) During the test, the top level of the raw material layer decreased with the burning of the waste.
Raw materials (waste and limestone) to maintain in the range of m
Were sequentially charged. In the steady state, the input speed of waste was always set at 40 kg / h.

(6) The temperature measured by the thermocouple attached to the surface of the lining brick in the second zone and the thermocouple attached to the free board space in the third zone is always maintained at 800 to 1400 ° C. The primary tuyere, 2
The amount of oxygen gas blown from the next tuyere, the third tuyere and the upper lance was adjusted.

That is, the unloading speed is high and the second
When the temperature of the zone and the zone of the third zone exceeded 1400 ° C., the oxygen gas from the primary tuyere was reduced.
Conversely, if the temperature of the second zone is lower than 800 ° C., 2
Oxygen gas was blown from the next tuyere and upper blowing lance. When the temperature of the third zone was lower than 800 ° C., oxygen gas was blown from the third tuyere and the upper lance.

(7) The temperatures of the molten slag and the molten metal were measured and determined at a predetermined temperature (1400 as in the case of Example 1).
と し た 1600 ° C.), pulverized coal was blown from the primary tuyeres. In the case where sample 6 is the case, if the calorific value of the waste itself is small, 1
A supplementary fuel supply from the next tuyere became necessary. Also, pulverized coal was blown from the secondary tuyere and the upper lance.

(8) By repeating the above (5) to (7), it is possible to derive the optimum amount of the supporting gas and auxiliary fuel to be blown (that is, the amount shown in the condition column of Table 7). did it. Here, nitrogen was blown in as an amount of about 1/10 of oxygen, but if the oxygen concentration was ≧ 50%, it was possible to adequately cope with it. In addition, even when the sample was changed (from sample 4 to sample 5 and from sample 5 to sample 6), it was possible to appropriately cope with the case.

Table 8 shows the results (actual results) obtained in the above tests.
Shown in The unit is the amount per ton of waste.

As indicated, a high-calorie energy gas mainly containing CO and H 2 containing little dioxins (indicated as exhaust gas in the table) and low-boiling heavy metals such as mercury, cadmium and lead were used. The concentrated dust could be recovered. The energy gas and dust were discharged outside the furnace through a gas outlet through a duct, and then separated and recovered by a hot cyclone.

Further, the concentration of hydrocarbons in the exhaust gas, especially hydrocarbons such as Cm Hn (m ≧ 5), which may cause pipe blockage, was completely negligible. Further, the concentration of hydrogen chloride in the exhaust gas was high because the temperature in each zone in the gasification and melting furnace was increased from that in Example 1 to promote gasification. Since it can be sufficiently removed by a known technique (for example, water treatment of exhaust gas), there is no problem in the process.

In addition, a molten metal and a molten slag mainly containing valuable metals such as iron and copper could be recovered.
The molten metal and the molten slag were discharged from the slag outlet to the outside of the furnace, and then separated and collected into a metal component and a slag component.

In Embodiment 2 in which the tuyeres of the first to third zones and the upper blowing lance are used at the same time, the combustion supporting gas can be uniformly blown into each zone in the gasification and melting furnace. Therefore, as compared with Examples 2 and 3 described below,
The superiority was recognized for the following items.

Reduction of oxygen consumption Reduction of auxiliary fuel (pulverized coal) consumption Reduction of dust amount Concentration of low-boiling heavy metals in dust Reduction of dioxins and hydrocarbon gas in energy gas

[0183]

[Table 8]

Example 3 Using the same vertical furnace (gasification melting furnace) as the furnace used in Example 2, and the same three kinds of wastes (samples 4, 5 and 6), the primary tuyere A gasification melting test of the waste was performed using only the upper lance. The test conditions (steady state) were set in the same procedure as in Example 2.

Table 9 shows the test conditions and Table 10 shows the test results (actual results). The unit is the amount per ton of waste.

As indicated, a high-calorie energy gas mainly containing CO and H2 containing little dioxins (denoted as exhaust gas in the table) and low-boiling heavy metals such as mercury, cadmium, and lead were used. The concentrated dust could be recovered. The energy gas and the dust were discharged outside the furnace through the gas outlet, and then separated and collected through a hot cyclone.

Further, the concentration of hydrocarbons in the exhaust gas, especially hydrocarbons such as Cm Hn (m ≧ 5), which causes pipe blockage, was negligible. Further, the concentration of hydrogen chloride in the exhaust gas was high because the gasification was promoted by raising the temperature of each zone in the gasification and melting furnace, but it can be sufficiently removed by a known exhaust gas treatment technology. No problem.

Further, a molten metal and a molten slag mainly containing valuable metals such as iron and copper could be recovered. The molten metal and the molten slag were discharged from the slag outlet to the outside of the furnace, and then separated and collected into a metal component and a slag component.

In the third embodiment using the upper blowing lance,
Since the combustion supporting gas could be relatively uniformly blown into each zone in the gasification and melting furnace, the lance of Example 2 was compared with the following Example 4 (when no upper blowing lance was used). The superiority was recognized for the items listed at the end of.

[0190]

[Table 9]

[0191]

[Table 10]

Example 4 The same vertical furnace (gasification and melting furnace) as the furnace used in Example 2 and the same three kinds of wastes (samples 4, 5 and 6) were used, and an upper blowing lance was used. Instead, a gasification melting test of the waste was performed using only the first to third tuyeres. The test conditions (steady state) were set in the same procedure as in Example 2.

Table 11 shows the conditions for performing the test, and Table 12 shows the test results (actual results). The unit is the amount per ton of waste.

As indicated, a high-calorie energy gas mainly containing CO and H2 containing almost no dioxins (indicated as exhaust gas in the table) and low-boiling heavy metals such as mercury, cadmium and lead. The concentrated dust could be recovered. The energy gas and the dust were discharged outside the furnace through the gas outlet, and then separated and collected through a hot cyclone.

Further, the concentration of hydrocarbons in the exhaust gas, especially hydrocarbons such as Cm Hn (m ≧ 5), which causes pipe blockage, was negligible. Further, the concentration of hydrogen chloride in the exhaust gas was high because the gasification was promoted by raising the temperature of each zone in the gasification and melting furnace, but it can be sufficiently removed by a known exhaust gas treatment technology. No problem.

Further, a molten metal and a molten slag mainly containing valuable metals such as iron and copper could be recovered. The molten metal and the molten slag were discharged from the slag outlet to the outside of the furnace, and then separated and collected into a metal component and a slag component.

[0197]

[Table 11]

[0198]

[Table 12]

Example 5 A waste gasification / melting test was conducted using a rigid furnace (gasification / melting furnace) having the configuration shown in FIG. In addition to the following, the number, arrangement and installation angle of the tuyere are as described below.
Same as in.

Quantity Primary tuyere: 4 Secondary tuyere: 4 Tertiary tuyere: 4 Arrangement Primary tuyere: equidistant every 90 degrees in the circumferential direction Secondary tuyere: 90 degrees in the circumferential direction Equidistant at every tertiary tuyere: Equidistant at every 90 degrees in the circumferential direction Installation angle of the tertiary tuyere (θ): θ = 90 ° or 30 ° The waste used in the above test is general municipal waste. And has a low calorific value of 5700 kcal per kg of waste. Table 13 shows the composition of this waste. This waste is compressed in advance to reduce the size to 10
Was molded into an RDF having a size of 50 mm from the above. Also,
The limestone used as an auxiliary material was a lump of 10 to 50 mm.

[0201]

[Table 13]

Table 14 shows the main experimental conditions. RDF is 1
60 kg was injected per hour. The amount of coke charged was 100 kg per 1 t of waste disposal amount. The supporting gas blown from the tuyeres 5-1 and 5-2 was slightly mixed with nitrogen gas based on oxygen gas.

[0203]

[Table 14]

In Comparative Example 1, 30 Nm 3 /
h, 7.5 Nm3 / h of oxygen is blown from the secondary tuyere,
No oxygen was blown from the third tuyere.

Example No. 1 to No. Even in 3, 1
Next, 30Nm3 / h, 7.5N from the tuyere
m3 / h of oxygen was blown. Further, in Example No. 1
Then, 1.0 Nm 3 / h of oxygen and the energy gas generated in Comparative Example 1 were burned from a tertiary tuyere installed at an angle of 90 ° with respect to the circumferential tangent of the gasification and melting furnace, and C was burned.
O2 and H2 O generated gas (CO2: H2 O:
N2 = 58: 22: 20) as a recycled gas.
5 Nm3 / h was blown.

Example No. In No. 2, oxygen was not blown from the tertiary tuyeres, but the gas after burning the energy gas generated in Comparative Example 1 was blown as 5.0 Nm3 / h as a recycle gas.

Example No. In No. 3, the installation angle of the tertiary tuyere was set to 30 degrees with respect to the tangent in the circumferential direction of the gasification and melting furnace, oxygen was not injected, and the gas after burning the energy gas generated in Comparative Example 1 Was blown as 5.0 Nm3 / h as a recycle gas.

Table 15 shows the test results. The obtained energy gas contained gases such as CO, CO2, methane, ethylene, and hydrogen (in the table, indicated as exhaust gas concentration), and at room temperature having 5 or more carbon atoms, liquid hydrocarbons were generated. Liquid hydrocarbons are gases at the top of the gasification and melting furnace due to high temperatures, but exist as liquids at room temperature.

In the comparative example in which oxygen or recycle gas was not injected from the tertiary tuyeres, 700 g / h of liquid hydrocarbons having 5 or more carbon atoms were recovered at room temperature. On the other hand, in Example No. 3 in which recycled gas and oxygen were blown from the third tuyere. In 1, the liquid hydrocarbon at room temperature is CO,
Since it was reformed to H2, the recovered amount was 175 g / h.
It decreased as compared with Comparative Example 1. In addition, CO and H2 contained in the exhaust gas by the reforming reaction of hydrocarbons which are liquid at normal temperature
, The calorific value of the recovered energy gas (in the table, indicated as exhaust gas calories) increased compared to Comparative Example 1.

In the case of Example No. 1 in which only the recycled gas was blown from the tertiary tuyeres. In the case of Example No. 2, the amount of hydrocarbon liquid at room temperature was Example 1 was the same as Example 1, but the amount of CO was increased by the reforming reaction. Increased compared to 1.

Example No. No. 3 is a case where only the recycled gas is blown from the tertiary tuyere installed at an angle of 30 degrees with respect to the tangent in the circumferential direction of the gasification and melting furnace. In this case, the blown recycled gas and the waste are discharged. The mixture of the hydrocarbons generated by the gasification was obtained in Example No. 2, the reforming reaction was promoted, the amount of liquid hydrocarbons generated was significantly reduced, and the calorie of the exhaust gas was also increased.

[0212]

[Table 15]

[0213]

According to the present invention, if the waste gas is incinerated in accordance with the method of the present invention using the gasification and melting furnace of the present invention, the organic matter contained in the waste is gasified and recovered as an energy gas, and the waste gas is recovered. Can be recovered as molten slag and molten metal, respectively.
As a result, it is possible to reduce the cost of landfilling general waste and industrial waste, which is a problem at present, and to use the generated by-product gas as a fuel for power generation.

When the reaction temperature in the gasification-melting furnace is increased, gasification is promoted, and it becomes possible to recover low-boiling heavy metals. Furthermore, by injecting a part of the energy gas as a recycled gas into the furnace, the efficiency of recovering the energy gas can be increased.

[Brief description of the drawings]

FIG. 1 is a schematic vertical sectional view showing a configuration of an example of a waste gasification and melting furnace of the present invention.

FIG. 2 is a schematic vertical sectional view showing the configuration of another example of the waste gasification and melting furnace of the present invention.

FIG. 3 is a schematic vertical sectional view showing the configuration of still another example of the waste gasification / melting furnace of the present invention.

FIG. 4 is an explanatory diagram of a blowing angle of a recycle gas into a gasification and melting furnace.

[Explanation of symbols]

1: Gasification and melting furnace body 2: Refractory brick 3-1: Gas discharge port 3-2: Gas discharge duct 4: Exhaust gas 5-1: Primary tuyere 5-2: Secondary tuyere 5-3: Tertiary Tuyere 6-1: Auxiliary fuel to be blown into primary tuyere 6-2: Auxiliary fuel to be blown into secondary tuyere 6-3: Auxiliary fuel to be blown into tertiary tuyere 7-1: Fuel support to be blown into primary tuyere 7-2: Combustion gas blown into secondary tuyere 7-3: Combustion gas blown into tertiary tuyere 7-4: Recycle gas blown into tertiary tuyere 7-5: Tertiary tuyere 8: flow of molten slag and molten metal 9: outlet of molten slag and molten metal 10: pusher 11-1: waste loading port 11-2: hopper 12: waste 13: molten slag And molten metal 14: packed bed mainly composed of carbide 15: mainly composed of waste Packing layer 16: Free board 17: Sounding device (raw material layer top level meter) 18: Sounding weight 19: Temperature converter (Device for converting thermocouple signals to temperature) 20: On the surface of the lining brick in the second zone Provided thermocouple 21: Thermocouple provided in the freeboard space of the third zone 22: Supporting gas 23: Auxiliary fuel 24-1: Upper blowing lance 24-2: Lance lifting device 25: Hot cyclone 26: Energy gas 27: Dust 28: Exhaust gas combustion chamber

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI F23G 5/50 ZAB F23G 5/50 ZABJ ZABH (72) Inventor Hirotaka Sato 4-33 Kitahama, Chuo-ku, Osaka-shi, Osaka Sumitomo Metal Industries Inside the corporation

Claims (6)

[Claims] 1. Gasification and melting of vertical waste in which the waste is burned, the organic matter in the waste is gasified and recovered as an energy gas, and the ash and metals in the waste are recovered as a melt. A furnace having a waste loading inlet for charging the waste and a gas outlet for discharging generated gas at an upper portion, and a molten slag and a molten metal outlet at a lower portion; A tuyere is provided between the inlet and the discharge port of the molten slag and the molten metal. Gasification of waste characterized by having means for measuring the level of waste entered, means for measuring the temperature in the vicinity of the tuyere in the middle stage, and means for measuring the temperature of atmospheric gas in the upper part of the furnace Melting furnace. 2. A method for gasifying and melting wastes using the waste gasification and melting furnace according to claim 1, wherein the wastes charged into the furnace from a waste charging inlet are: By the reaction in each zone, energy gas mainly composed of CO and H ₂ , molten slag and molten metal were collected, and the former was recovered from a gas outlet provided in the upper part of the furnace, and the latter was provided in the lower part of the furnace. A method for gasifying and melting waste, comprising recovering molten slag and molten metal from outlets. [First zone] Amount of combustible gas and auxiliary fuel determined from the level value of the charged waste are blown from the lower tuyere, and the carbide generated in the second zone is burned and gasified to reduce gas. The ash and the metals contained in the carbides are generated and melted to form molten slag and molten metal. [Second zone] Amount of flammable gas and auxiliary fuel determined from the temperature measurement value near the middle tuyere are blown from the middle tuyere, and the reducing gas generated in the first zone is subjected to secondary combustion,
The waste loaded from the waste loading inlet is dehydrated and heated to thermally decompose into carbide and hydrocarbon gas. [Third zone] Amount of flammable gas and auxiliary fuel determined from the temperature measurement value of the atmospheric gas in the upper part of the furnace are blown from the upper tuyere, and the hydrocarbon gas generated in the second zone is thermally decomposed. Energy gas containing CO and H ₂ as main components. 3. Burning the waste, gasifying organic matter in the waste and recovering it as an energy gas, and gasifying low-boiling heavy metals in the waste and recovering it as dust accompanying the energy gas. A vertical waste gasification and melting furnace for recovering ash and metals in waste as a melt, a waste loading inlet for charging the waste at the top, and gas and dust generated. A gas discharge port to be discharged and dust collecting means connected to the gas discharge port via a gas discharge duct; a discharge port for molten slag and molten metal at a lower portion; A tuyere capable of independently injecting a supporting gas and an auxiliary fuel between a metal outlet and a tuyere, which burns and gasifies carbides generated by dehydration and pyrolysis of waste. Having at least one stage of tuyere in the height direction including the tuyere of the above, and having an upper blowing lance at the upper part of the furnace capable of blowing a combustible gas and an auxiliary fuel which can be raised and lowered into the furnace. And a means for measuring the level of the charged waste, a means for measuring the temperature in the vicinity of the tuyere in the middle stage, and a means for measuring the temperature of the atmospheric gas in the upper part of the furnace. Gasification and melting furnace for waste. 4. A waste gasification / melting method performed by using the waste gasification / melting furnace according to claim 3, wherein the waste charged into the furnace from a waste charging inlet is: By reaction in each zone, energy gas mainly composed of CO and H ₂ and dust containing low-boiling heavy metals, molten slag and molten metal are collected, and the former is recovered from a gas outlet provided in the upper part of the furnace. A gasification and melting method for waste, comprising separating into energy gas and dust, and collecting the latter from a discharge port of molten slag and molten metal provided in a lower part of the furnace. [First zone] A combustion-supporting gas and, if necessary, auxiliary fuel are blown from the lower tuyere to burn and gasify the carbide generated in the second zone to generate a reducing gas and to reduce ash contained in the carbide. The metals are melted into molten slag and molten metal. [Second Zone] The supporting gas and, if necessary, auxiliary fuel are blown from the tuyere in the middle stage and / or the upper blowing lance,
The reducing gas generated in the zone is secondarily burned, and the waste charged from the waste loading inlet is dehydrated and heated to thermally decompose into carbide and hydrocarbon gas, while gasifying low-boiling heavy metals. [Third Zone] The supporting gas and, if necessary, auxiliary fuel are blown from the upper tuyere and / or upper blowing lance,
The hydrocarbon gas generated in the zone is thermally decomposed to CO and H ₂
As the main component, and gaseous low-boiling heavy metals as dust. 5. A method in which a part of the recovered energy gas is directly blown into the third zone of the gasification and melting furnace as a recycle gas, or at least a part of the blown energy gas is burned to produce CO ₂ and / or H _{2. The} method for gasifying and melting waste according to claim 2, wherein the gas containing 2O is blown as a recycled gas, or a mixed gas of the recycled gas and oxygen is blown. 6. Injection of a recycle gas or a mixture gas of a recycle gas and oxygen is performed using a tuyere provided at an angle θ of 0 ° <θ <90 ° with respect to a circumferential tangent of the gasification and melting furnace. The method for gasifying and melting waste according to claim 5.